Repair Video of Peale's Galaxian PCB (and a little arcade game architecture)

ajcrm125

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Repair Video of Peale's Galaxian PCB (and a little arcade game architecture)

Hey Peale, sorry I wasn't able to coordinate a time for you to come down and work with me through the repair. With my work/life schedule I'm finding that I tend to fix games by spending 5 mins here, 10 mins there.. etc throughout the day.

Anyways.. I did the next best thing and documented the process here.
Enjoy!
http://www.youtube.com/watch?v=fFQ9pEk5ANU

 
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Maybe you could recommend or make a video going through the Fluke and how it is hooked up and used (for the novice like me). Been watching your other videos, thanks again.
 
Great video! I too would like to see how the fluke is used to interact with the
game board while running.

How did you determine through probing the rom was bad? I see the video evidence but what testing did you do between identifying the section of the board to finding the bad rom?

For a novice.. how can you spot various different segments of the board.. ram, rom, etc. Is it just knowing chip values?

What is the monitor you use for testing? Is it a commodore one?

Malice95
 
yeah man thats really cool.. but it seems you need the equipment in order to diagnose some of the problems of these boards, and from the looks of the equipment they are pretty old them selves, also you need to KNOW how to use that equipment ... but very cool indeed
 
yeah man thats really cool.. but it seems you need the equipment in order to diagnose some of the problems of these boards, and from the looks of the equipment they are pretty old them selves, also you need to KNOW how to use that equipment ... but very cool indeed

Exactly. You summed it up exactly. I don't see how you could debug some of these problems without a Microprocessor emulator (which is what the fluke is).
I mean this example wasn't that bad in that someone shotgunning the board could try replacing a ROM and see if helped but very rarely have my repairs gone that way.

So I guess that being said these videos are prob more for entertainment/educational value than instructional.
 
Exactly. You summed it up exactly. I don't see how you could debug some of these problems without a Microprocessor emulator (which is what the fluke is).
I mean this example wasn't that bad in that someone shotgunning the board could try replacing a ROM and see if helped but very rarely have my repairs gone that way.

So I guess that being said these videos are prob more for entertainment/educational value than instructional.

just one question... not once did you think it was a resistor or cap?? Just by looking at the symptoms of the board, how come you didnt revert to one of them instead of a CHIP??

I guess in other words how do you weed out them and go straight for a chip?

just wondering
 
just one question... not once did you think it was a resistor or cap?? Just by looking at the symptoms of the board, how come you didnt revert to one of them instead of a CHIP??

I guess in other words how do you weed out them and go straight for a chip?

just wondering

99% of arcade games designs are digital logic. Resistors and caps are only used to clean up the digital signals or in sections of the audio circuity.

Now it is possible that a resistor blowing could cause a digital input to switch and would cause some sort of problem,.. but it's not very common. The majority of the resistors on the board are for pullup circuits like your inputs (joystick, buttons, etc) which would never show a symptom like this. And most of the caps on the game PCB are for power supply decoupling (making clean power).
 
How did you determine through probing the rom was bad? I see the video evidence but what testing did you do between identifying the section of the board to finding the bad rom?
I found that the upper 2 bits of the data byte coming out of the ROM was always high. This meant that a few bits color would always be blitted to the screen even if you wanted nothing at all. I shorted these pins out to ground on the PCB and once I saw the lines disappeared.. I knew I found the culprit.


For a novice.. how can you spot various different segments of the board.. ram, rom, etc. Is it just knowing chip values?
Anthing that looks like "74<some letters><some #'s>" is a TTL part.
See my webpage here on how to identify those and what they do:
http://www.onecircuit.com/node/27

Roms have a larger form-factor (I.E. they are wider than the other chips) and have common numbering. Rams are smaller but have common numbering as well. In this case the schematics clearly labeled them as ROMs and RAMs so all I had to do was look at the location ID on the schematic to find them on the board.

What is the monitor you use for testing? Is it a commodore one?
Yep. Commodore 1084S. Some older Apple and Sony monitors can be used as well.
 
I could do a Fluke Video...right now I'm pretty swamped and kinda want a couple days off in the near future but I'd love to do one.

And yeah you do need the Fluke for some tests but not always, it just makes some of the testing a LOT faster. For example though I could use the SI test rom to test a BOOTING Si board just as fast as doing it with the Fluke. Oh the other hand, if the SI board won't even boot the test rom, THEN the Fluke could come in handy to find out why.

PS I havent watched the vid yet but looking forward to it...at work right now no videos allowed (per myself lol).
 
Maybe you could recommend or make a video going through the Fluke and how it is hooked up and used (for the novice like me). Been watching your other videos, thanks again.

That may work. I have another board or 2 with complete random garbage all over the screen. Can show the process of using the Fluke to bring that guys back to life as I'm sure it's an ROM/RAM addressing issue.
 
That may work. I have another board or 2 with complete random garbage all over the screen. Can show the process of using the Fluke to bring that guys back to life as I'm sure it's an ROM/RAM addressing issue.

That would be cool, thanks. The TTL logic comparator is a cool device. Where did you pick that up at?
 
What are some of the most common Fluke pods necessary to interface for arcade board repair? Lets say boards older then 1990 in general?

Thanks,
Mike
 
I have a 6502, 8080, and Z80 (which can be upgraded to Z80A). I also have an 8088 that I picked up for the hell of it in case I can get paid to actually fix an old XT sometime ;-) The 6502 is going to be hard to find/most expensive out of that bunch. This fluke gear is NOT CHEAP unless you can find a deal on it.

Other pods from there would be 68k (VERY VERY NOT CHEAP), and pods for pin boards like 6800.
 
The probe for the 9010a is a great tool too cuz it allows you to sample address/data lines on multiplexed systems.
 
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